Do "Moderate" Drinkers Have Reduced Mortality Risk? A Systematic Review and Meta-Analysis of Alcohol Consumption and All-Cause Mortality.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of prospective observational cohort studies
PubMed 26997174 · doi:10.15288/jsad.2016.77.185
What was done
A systematic review and meta-regression analysis of 87 prospective cohort studies (3,998,626 individuals and 367,103 deaths) evaluated the relationship between alcohol consumption and all-cause mortality. The study examined whether misclassifying former and occasional drinkers as lifetime abstainers (abstainer bias), along with other study-level quality characteristics, accounted for the previously observed J-shaped mortality curve.
What was found
Without adjustment, low-volume drinkers (1.3–24.9 g ethanol/day) had a reduced mortality risk (RR = 0.86, 95% CI [0.83, 0.90]), occasional drinkers (<1.3 g/day) showed similar reduction (RR = 0.84, 95% CI [0.79, 0.89]), and former drinkers had elevated mortality (RR = 1.22, 95% CI [1.14, 1.31]). After adjusting for abstainer biases and study quality, low-volume drinkers had no significant mortality reduction (RR = 0.97, 95% CI [0.88, 1.07]). Sub-analyses of higher-quality, bias-free studies likewise showed no survival benefit for low-volume drinkers.
Why it matters
Apparent health and survival benefits of moderate drinking appear to be artifacts of methodological error, specifically comparing moderate drinkers against reference groups containing unhealthy former drinkers. Accounting for these biases eliminates the apparent net mortality benefit of low-volume alcohol intake.
Limits
The analysis is restricted to observational cohort studies, which rely on self-reported alcohol intake and remain vulnerable to residual confounding. The abstract does not report beverage-specific risks, drinking patterns (e.g., binge vs. regular consumption), or cause-specific mortality outcomes.
Cited by
- supports When studies adequately control for confounding factors like the healthy user effect and sick quitter bias, most or all of the protective effects of alcohol on disease risk are eliminated.